Acting Director Kenneth E. Melson and the U.S. attorney in Phoenix are ousted amid fallout from Operation Fast and Furious.

Reporting from Washington — Justice Department officials have removed the head of the beleaguered ATF and the U.S. attorney in Phoenix — an attempt to provide a fresh start for the agency whose employees had expressed a lack of confidence in their leadership since the Operation Fast and Furious gun-tracking scandal.

But the moves did not satisfy congressional Republicans, who vowed to ratchet up their investigation of the failed program that sent hundreds of guns to Mexican drug cartels. They are preparing for a new round of hearings into who was involved at other law enforcement agencies, including the FBI, the Drug Enforcement Administration and the Justice Department.

The announcements Tuesday that Kenneth E. Melson, acting director of the Bureau of Alcohol, Tobacco, Firearms and Explosives, and U.S. Atty. Dennis K. Burke were leaving their posts came after Obama administration officials said they had received messages from ATF employees expressing a deep "lack of confidence" in the leadership.

"We heard from special agents in charge and field agents, they reached out to us," said an administration official, who like other officials interviewed spoke on the condition of anonymity because the investigation is ongoing.

Melson was called to the deputy attorney general's office Friday and told it was in the "best interest" of the bureau that he move on, and he agreed, sources said. He is being transferred to the Office of Legal Policy, a division in the Justice Department that helps on long-range planning issues, where he will become senior advisor on forensic science.

Burke, whose office provided the legal guidance for Fast and Furious, acknowledged to Justice Department officials in Washington this month that a clean slate in Phoenix was needed for federal law enforcement officials working the U.S.-Mexico border, congressional sources said.

In addition to Burke, who is leaving government service, Emory Hurley, the top assistant federal prosecutor in Phoenix, was moved Monday from the criminal division in the U.S. attorney's office in Phoenix to handling civil matters.

In an email to the ATF staff, Melson, who has maintained he was kept in the dark about details of the guns program, did not mention Fast and Furious. Instead, he said: "I look forward to hearing nothing but good news and great accomplishments from ATF. God speed."

During a closed-door session with congressional investigators this month, Burke defended Fast and Furious as a legitimate operation. But he also acknowledged that mistakes were made and he was accountable. The months of controversy have worn on him; sources said he was not sleeping and had lost weight.

Despite the management changes in Washington and Arizona, congressional investigators remain determined to get to the bottom of the Fast and Furious debacle. About 2,000 guns were illegally purchased under surveillance and then lost by agents trying to follow them. During the 15-month program, a U.S. Border Patrol agent was killed and numerous Fast and Furious weapons turned up at crime scenes in Mexico.

Rep. Darrell Issa (R-Vista), chairman of the House Oversight and Government Reform Committee, said his panel would "continue its investigation to ensure that blame isn't offloaded on just a few individuals for a matter that involved much higher levels of the Justice Department."

"This isn't going to change anything," one congressional investigator said of the management shake-up.

Sen. John Cornyn (R-Texas) said Melson should leave altogether.

"Instead of reassigning those responsible for Fast and Furious within the Department of Justice," he said, "Atty. Gen. [Eric] Holder should ask for their resignations and come clean on all alleged gun-walking operations."

B. Todd Jones, the U.S. attorney in Minneapolis, who was picked to replace Melson as the ATF's acting director, sent an email to all employees saying, "I know it's been a challenging time for this agency, and for many of you." He added that "we have important work to do" and that Holder wanted him to bring "stability and leadership" to the long-troubled agency.

The White House is still hoping to get Senate confirmation for Andrew Traver, head of the ATF in Chicago, whom the president nominated as permanent director last year. His nomination has stalled over opposition by the National Rifle Assn., which has opposed a string of selections to run the ATF.

An administration source said Tuesday that Jones is a former Marine and has extensive leadership experience to help the agency past the Fast and Furious scandal.

"He's got a really good management reputation, which is certainly what they need right now," the official said. "There was a premium put on that. He can get in there and turn the page, give them a fresh start."